Some modern computing computer architectures rely on a multi-tiered environment. A load balancer or proxy might dispatch work to a server in the tier above it. Under high load conditions additional dispatchers and servers might be automatically provisioned via software so that the dispatchers can handle a queue of incoming work requests. In another scenario a server might be experiencing high CPU load and a network appliance might be provisioned to intercept requests from the network to accelerate encryption/decryption of a network packet.
A problem that arises is that under low load conditions the additional dispatchers, servers and network appliances sit idle. This can result in wasted power consumption, an under-utilized network and a deterioration of network efficiency. The same is the case for a high load condition as well as in an occurrence of a hardware failure.
Another problem that arises in a multi-tier processing system occurs when one tier of the multi-tier processing system becomes unavailable, as this condition can limit the accessibility of other tiers.
Of relevance to these teachings is co-owned US Patent Publication No. 2007/0053285 A1, directed to recovering faults in a token ring network in which a command is sent at regular intervals to a control device. A control device re-starts its timer upon receipt of a command, and bypasses all of the ports under its control if another command is not received prior to expiration of that timer (e.g., double the regular interval period).